This document discusses building green or sustainable architecture. It defines building green as constructing buildings in an environmentally-friendly way from site planning to deconstruction. Building green can help reduce energy and resource use while creating a healthier environment for occupants. It is achieved through practices like sustainable design, alternative energy sources, and use of natural and recycled materials. The LEED green building rating system, established in the US, provides standards and certification for green construction projects and has influenced other countries.